An innovative and sustainable approach to spray paint graffiti removal from Istrian stone through the silica sol-gel chemistry: A preliminary assessment

A sustainable methodology to synthesise and screen libraries of new low-environmental impact products, suitable for removing graffiti and murals from historic building, masonries and stone artworks has been developed. This approach provided a novel series of two-component systems by combining silica sol-gel chemistry and dimethyl carbonate. The solid matrixes were hybrid silica gels, which were synthesised in basic conditions by using ethylene and propylene glycols as organic co-solvents. Dimethyl carbonate (DMC) was the green organic solvent to load into the gel. The efficiency of three new systems in adsorbing/trapping commercial red aerosol spray paint was investigated through an ad hoc test tube extraction evaluation and on mock stained samples of Istrian stones. Data provided byNMRspectroscopy and FT-IR spectroscopy led to the identification of a promising cleaning agent, paving the way to its full characterisation and features improvement.